Advice needed

After an extensive search I have finally found a base gun to make original blaster carbines for my movie "The Mandalorian Wars". This means that I don't need to use dozens of EE-3's! However, I need help to cast the new carbine up.
As they're for a movie they need to be fairly robust but I really do not know how to go about casting them.
Also which would be better, Rubber or Resin? (I've done neither so any advice welcome)

Jo

Just the top of my head i would say rubber.. that's what most props are made out of anyway in the movies... either that or silicone..

I have a resin EE-3 and I would say rubber. Resin is more brittle and will break if dropped on the wrong spot.